Roger Johnson is set to become Wolves' highest earner on a four-year deal worth around £40,000-a-week

Mick McCarthy expects to finalise the details of Roger Johnson’s switch from ­Birmingham today after the defender completes a medical at Molineux.

Club owner Steve Morgan has already approved £12m of spending with Spurs’ midfielder Jamie O’Hara completing his ­permanent £5m move after spending the second half of last season on loan.

And Morgan appears keen to sanction at least one more high-profile signing to ­ensure Wolves avoid a repeat of last ­season’s brush with relegation.

Johnson, 28, is set to become the club’s highest earner on a four-year deal worth around £40,000-a-week as Carson Yeung’s fire sale at St Andrew’s continues.

Birmingham owner Yeung, facing trial for alleged money laundering in Hong Kong, lowered his £10m valuation of the former Cardiff defender to push through the deal.

Blues skipper Barry Ferguson is also on the way out to join Blackpool, while Scott Dann, Liam Ridgewell, Ben Foster and Cameron Jerome are all likely to be sold to ease the club’s £30m debts.

McCarthy also has an interest in Ridgewell and may be ready to take on bitter rivals West Brom in the contest to sign the ­versatile defender.

But McCarthy is delighted to have grabbed his No.1 target Johnson. The player spent yesterday at Wolves’ training ground, thrashing out the finer details of his four-year deal and a fee which equals that paid for Steven Fletcher from Burnley.